Researchers at the BIST Community centre ICIQ have developed a hybrid photoelectrode that combines a light-absorbing material with molecular catalysts, achieving efficient and stable water oxidation under simulated sunlight.
Researchers from the group of Prof. Antoni Llobet at the Institute of Chemical Research of Catalonia (ICIQ) have developed a new strategy to combine molecular catalysts with a light-absorbing semiconductor for solar-driven water oxidation. The approach uses a self-assembled molecular layer to bring the two components together, achieving efficient and stable oxygen production from water under simulated sunlight. The study has been published in the Journal of the American Chemical Society.
Solar-driven water splitting is being studied as a way of producing hydrogen, a storable fuel, using sunlight and water. The process involves two complementary reactions: the reduction of protons to produce hydrogen and the oxidation of water to produce oxygen. Water oxidation is particularly challenging because it involves the transfer of four electrons and four protons and the formation of an oxygen-oxygen bond. It is also one of the steps that limits the efficiency and stability of photoelectrochemical systems.
The ICIQ researchers focused on this part of the process, combining bismuth vanadate (BiVO4), a semiconductor that absorbs light, with a molecular catalyst capable of oxidising water. The two components were assembled into a thin molecular layer through non-covalent supramolecular interactions. A second molecular component was incorporated as an electron relay to facilitate electron transfer via quantum tunnelling, between the semiconductor and the molecular catalyst.
“This work is especially meaningful because it demonstrates that the immobilization of molecular catalysts on semiconductors through non-covalent interactions can lead to extremely efficient and robust photoelectrochemical water oxidation systems, taking advantage of the best of the two worlds: solid state materials and molecular science. It highlights the potential of tuning molecular complexes to facilitate their incorporation into photoelectrochemical devices and improve their performance and opens new possibilities for the development of more sustainable technologies for solar energy conversion,” explains Dr. Paula Tris-Marzo, first author of the study and researcher in Prof. Antoni Llobet’s group.
The self-assembled approach developed by the ICIQ team provides a new strategy to synergistically combine molecular components at the semiconductor surface. This, enhances light absorption while at the same time substantially improves the robustness of the whole device thanks to the quantum tunnelling path.
Reference publication:
Water Oxidation by Molecular Catalyst Bilayers Self-Assembledon Bismuth Vanadium Oxide (BVO) Photoelectrodes
Tris-Marzo, P.; Vecchi, P.; Gil-Sepulcre, M.; Meyer, G. J.; Llobet, A.
J. Am. Chem. Soc. 2026, 148 (32), 34604-34614
DOI: 10.1021/jacs.6c08907
